The problem of providing a sealed connection between two tubes or pipes, at least one of which is rigid or semi-rigid, e.g. is made of metal or of plastic, has already received a wide range of solutions that differ, in particular, by the presence or the absence of a gasket. Thus, when one of the elements of the coupling is made of a flexible material, such as rubber, a gasket is unnecessary (see EP-A1-0 401 083), whereas in couplings where beth of the elements to be assembled together are rigid or semi-rigid, a gasket is interposed between said elements, as shown in FR-A-2 628 819 or FR-A-2 632 707, for example, where FR-A-2 632 707 is in the name of the Assignee. In spite of the solutions that have already been proposed, a need continues to exist in industry, and in particular in the motor industry, for a coupling to connect together two rigid or semi-rigid tubes or pipes in such a manner as to make it possible to establish a connection that is not only quick, simple, and reliable, but that is also proof against the fluid conveyed thereby, be it a liquid (water, oil, gasoline), or a gas such as air, and this should apply to couplings that are releasable or not, as the case may be.
Consequently, a general object of the invention is to provide a rapid-action coupling device which enables the above results to be obtained.
Another object of the invention is to provide such a rapid-action coupling device having characteristics, and in particular sealing characteristics, that are maintained over time.
Another object of the invention is to provide such a device enabling different types of tubes or pipes to be coupled together, for example pipes made of plastic or tubes made of steel and having a collar, the coupling being releasable or not as the case may be, depending on practical requirements.
Yet another object of the invention is to provide such a device that makes it easy to monitor the connection it serves to establish, and that is also extremely simple to maintain when it provides a releasable coupling, thereby providing considerable advantages in after-sales service, particularly in its application to the motor industry.